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Journal ArticleDOI

Vibro-acoustic behavior of a multilayered viscoelastic sandwich plate under a thermal environment:

TL;DR: In this paper, the authors present numerical simulation studies on the vibration and acoustic response characteristics of a multilayered viscoelastic sandwich plate in a thermal environment, where the critical buckling temperature and vibration response were obtained using finite element method while sound radiation characteristics are obtained using boundary element method.
Abstract: This article presents numerical simulation studies on the vibration and acoustic response characteristics of a multilayered viscoelastic sandwich plate in a thermal environment. Initially the critical buckling temperature is obtained followed by free and forced vibration analyses considering the pre-stress due to the imposed thermal environment in the plate. The vibration response predicted is then used to compute the sound radiation. The critical buckling temperature and vibration response are obtained using finite element method while sound radiation characteristics are obtained using boundary element method. It is found that resonant amplitude of both the vibration and acoustic response decreases with increase in temperature. The influence of core thickness, number of layers, type of thermal field, and type of viscoelastic core material on vibration response sound radiation characteristics are studied in detail.
Citations
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Journal ArticleDOI
07 Oct 2021
TL;DR: In this article, a finite-element-based numerical formulation is presented to evaluate the nonlinear deflections of magneto-electro-elastic sandwich skew plates with a viscoelastic core.
Abstract: This work presents a finite-element-based numerical formulation to evaluate the nonlinear deflections of magneto-electro-elastic sandwich skew plates with a viscoelastic core and functionally grade...

11 citations

Journal ArticleDOI
TL;DR: A numerical scheme is prepared using the higher-order shear deformation type of kinematic model with the help of a coupled finite and boundary elements (FE–BE) to evaluate the vibroacoustic responses of laminated composite sandwich curved shell panels.
Abstract: In this paper, a numerical scheme is prepared using the higher-order shear deformation type of kinematic model with the help of a coupled finite and boundary elements (FE–BE) to evaluate the vibroacoustic responses of laminated composite sandwich curved shell panels The panel is under the influence of a harmonic point load Further, an FE–BE combined technique is utilized to prepare a generic computer code (MATLAB environment) for the numerical prediction via the proposed mathematical formulation The structural frequency and the subsequent sound relevant data are obtained by solving the final form of the multiphysics model In this regard, the structural system equation is derived through Hamilton’s principle and the Helmholtz wave equation for the computation of acoustic responses The performance of the proposed scheme is established initially through the convergence and the corresponding validation studies The comparison cases are made with the available published benchmark frequency (free vibration) as well as the acoustic data Appropriate numbers of numerical examples are solved to draw the meaningful inferences of various factors to show the significant influences on the acoustic radiation responses of the curved sandwich panel type of structural components The curvature ratio is showing the accentuated influences on the sound radiation responses for the low-frequency ranges whereas the increase in the thickness ratio, ie the ratio of core to face leads to an accentuated radiated sound power

9 citations

Journal ArticleDOI
TL;DR: In this paper, a theoretical model for calculating the modal density and mode counts of sandwich panels with composite face sheets in thermal environments is presented, where the Hamilton's principle based on an improved ordinary sandwich panel theory is applied.

8 citations

Journal ArticleDOI
TL;DR: In this article, the effect of static load on the vibro-acoustic behavior of clamped rectangular plates with various geometric imperfections is further investigated in an effective method applying static load to the plate subjected to dynamic excitations is proposed in the experiment.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the buckling, vibration and sound transmission characteristics of the simply supported sandwich plate with trapezoidal corrugated core in thermal environment were investigated. But the authors were not concerned with the structural properties of the plate.
Abstract: The present study is concerned with the buckling, vibration and sound transmission characteristics of the simply supported sandwich plate with trapezoidal corrugated core in thermal environment bas...

5 citations

References
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Book
30 Jun 1999
TL;DR: The Inverse Problem: Cylindrical NAH. as discussed by the authors The Inverse problem: Planar NAH and the Inverse NP-hardness of planar plane waves.
Abstract: Preface. Fourier Transforms & Special Functions. Plane Waves. The Inverse Problem: Planar NAH. Cylindrical Waves. The Inverse Problem: Cylindrical NAH. Spherical Waves. Spherical NAH. Green Functions & the Helmholtz Integral. Index.

1,032 citations


"Vibro-acoustic behavior of a multil..." refers background or methods in this paper

  • ...To understand why the concept of replacing the actual velocity distribution with a spatially averaged uniform rms velocity works, the alternative expression for sound power (using Rayleigh’s Integral) as shown by Williams [18] is considered: ! ð Þ 1⁄4 0ck 2 4 Z Z...

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  • ...To understand why the concept of replacing the actual velocity distribution with a spatially averaged uniform rms velocity works, the alternative expression for sound power (using Rayleigh’s Integral) as shown by Williams [18] is considered: !ð Þ ¼ 0ck 2 4 Z Z S Z Z S _U x0, y0ð Þ sin kRð Þ kR U x, yð Þdsds0 ð34Þ In the above equation R ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi x x0ð Þ2þ y y0ð Þ2 q where x yð Þ and x0 y0ð Þ are co-ordinates of two different point on the plate, S or S’ represents the plate area, _U is the normal velocity of the plate (assumed to be harmonic), and _U is its complex conjugate....

    [...]

  • ...Temperature-dependant material properties of visco-elastic core materials EC2216 and DYAD 606 [18]: (a) shear modulus, (b) material loss factor....

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Journal ArticleDOI
TL;DR: In this article, an efficient method for finite element modeling of three-layer laminates containing a viscoelastic layer is described, and modal damping ratios are estimated from undamped normal mode results by means of the modal strain energy method.
Abstract: An efficient method is described for finite element modelling of three-layer laminates containing a viscoelastic layer. Modal damping ratios are estimated from undamped normal mode results by means of the modal strain energy method. Comparisons are given between results obtained by the MSE method implemented in NASTRAN, by various exact solutions for approximate governing differential equations, and by experiment. Results are in terms of frequencies, modal damping ratios, and mechanical admittances for simple beams, plates, and rings. Application of the finite element -- MSE method in design of integrally damped structures is discussed.

542 citations


"Vibro-acoustic behavior of a multil..." refers methods in this paper

  • ...Johnson and Kienholz [2] described finite element based modal strain energy method to obtain modal damping ratios....

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Book
11 Jul 1996
TL;DR: In this article, the authors present a time-stepping method for convective heat transfer with phase change problems and linear Steady State Problems, and a non-linear heat-conduction analysis.
Abstract: Conduction Heat Transfer and Formulation. Linear Steady State Problems. Time Stepping Methods for Heat Transfer. Non--Linear Heat Conduction Analysis. Phase Change Problems----Solidification and Melting. Convective Heat Transfer. Nomenclature. Index.

329 citations

Journal ArticleDOI
TL;DR: In this article, the authors re-examined the definition of loss factor in terms of energy quantities, particularly as it applies to composite viscoelastic systems, and proposed simple relations which express the loss factors of series-parallel arrays of massless VRSs.
Abstract: The definition of loss factor in terms of energy quantities is re‐examined, particularly as it applies to composite viscoelastic systems. A restatement of this definition in terms of a corresponding viscoelastic spring is used to show that this definition is extremely useful for massless (ideal viscoelastic spring) systems, but may be applied unambiguously to spring systems with a single attached mass only at resonance. Simple relations are presented which express the loss factors of series‐parallel arrays of massless viscoelastic springs in terms of properties of the individual components. Implications of these relations in damping of composite structures are discussed. (This work was supported in part by the Aeronautical Systems Division, U. S. Air Force.)

319 citations


"Vibro-acoustic behavior of a multil..." refers background in this paper

  • ...Ungar and Kerwin [1] were the earlier researchers who found that the modal loss factor can be obtained by calculating the ratio of the dissipating energy to the total structural energy, using modal strain energy method....

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